The effect of metal thickness, overlayer and high-k surface treatment on the effective work function of metal electrode

We demonstrate that the effective work function (EWF) of atomic layer deposited (ALD) TiN electrodes is a function of the TiN film thickness and that the metal/dielectric interface and the bulk metal film influence this measured response. It is shown that anneal treatments and chemical processing of the underlying dielectric surface prior to electrode deposition may be exploited to modify the effective work function of metal electrodes. The effect of physical vapor deposited (PVD) and ALD metal overlayers on the effective work function of metal electrodes is also presented.